Intergroup relations and home range use in Verreaux's sifaka (Propithecus verreauxi)

Abstract

Relationships between neighboring groups feature prominently in socioecological theory, but few empirical studies have focused on the effects of neighbors on the behavior of primates. Interactions between neighboring groups are most conspicuous during intergroup encounters, but the likelihood of encounters with neighbors can also affect ranging and activity patterns indirectly, and, as a result, behavioral patterns in areas of exclusive use may differ from those in overlap areas of adjacent home ranges. The aim of this study was to examine intergroup relations and spatial variation in home range use in Verreaux's sifaka (Propithecus verreauxi) during the annual mating season. Based on 230 hr of focal animal data collected from ten members of five adjacent groups, we found that behavioral patterns and patterns of resource utilization were not markedly different between areas of exclusive use and overlap areas of adjacent home ranges. Group cohesion tended to be higher in overlap than in core areas, but the proportion of time spent resting and foraging did not differ between these two areas. However, dominant males exhibited a higher scent-marking rate in overlap areas. Observations during intergroup encounters revealed that chases between males occurred frequently, whereas fights involving physical contact were not observed. We also found that the intergroup dominance hierarchy depended on the relative group size or the number of males in each group, with groups of lower dominance rank exhibiting a tendency to sleep proportionally more often in their core areas. The results of this study suggest that in primate species with a moderate level of intergroup aggression, such as Verreaux's sifaka, the possibility of encountering neighbors in areas of home range overlap does not exert strong influence on their behavior and resource utilization.

A Preliminary Assessment of Sifaka (Propithecus) Distribution, Chromatic Variation and Conservation in Western Central Madagascar

“…Despite the limited number of observation days, the low intergroup encounter rate we report is consistent with observations in other sifaka species (Irwin 2006;Benadi et al 2008). On the other hand, the reactions of all individuals of P. coronatus observed during intergroup encounters in Badrala differed from those reported by Irwin (2006) for P. diadema in Tsinjoarivo and by Benadi et al (2008) for P. verreauxi in Kirindy.…”

“…On the other hand, the reactions of all individuals of P. coronatus observed during intergroup encounters in Badrala differed from those reported by Irwin (2006) for P. diadema in Tsinjoarivo and by Benadi et al (2008) for P. verreauxi in Kirindy. In these two studies the most frequently observed reactions were agonistic among neighboring groups.…”

Home range and seasonality of Yunnan snub‐nosed monkeys

“…These issues are methodological and biological and environmental factors influencing home range estimates will not be considered here and instead dealt with elsewhere. The biological and environmental factors are group size (de Ruiter 1986;Bleisch 1995;Ostro et al 1999a;Dias & Strier 2003), diet types (Harrison, 1983), food distribution and availability (Clutton-Brock 1975;Milton 1980;Boinski 1987;Zhang 1995;Li et al 2000), water availability (Altmann & Altmann 1970;Chapman 1988), sleeping site or resting site location (Rasmussen 1979;Harrison 1983) and the presence of other groups (Wrangham et al 2007;Benadi et al 2008).…”

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“…For instance, the length of daily travel is shortened in some species when high-quality food is rare (e.g., Trachypithecus pileatus [8], Hylobates lar [9]), conversely, other species move further to look for high-quality food resources (e.g., Colobus angolensis [10], Trachypithecus leucocephalus [11]). Ranging behavior and habitat use may also be influenced by other factors such as rainfall [12], group size [13], forest structure [4], water availability [14], location of dormitory [5], intergroup relationships [15], and parasite avoidance [16]. Nevertheless, crop-raiding primates having access to locally concentrate and high-quality food are thought to have also small home ranges that can be affected by the intensity of the human-primate conflict.…”